A polyamide is one of the polymers which are frequently used as engineering plastics for a very wide range of applications.
A foamable polyamide composition is of significant commercial interest and may be used as a light-weight material in aeronautical or motor vehicle, packaging or sound insulation applications, etc.
The foamable polyamide composition may be prepared by chemical methods. For instance, U.S. patent application publication No. 2006/0167124 discloses an expandable polyamide composition comprising at least one isocyanate function, a polyamide and a compound comprising at least one carboxylic acid function, and polyamide foams obtained therefrom.
For particular applications, such as a motor vehicle application, required is a foamable polyamide composition which is capable of providing polyamide foams having a higher foaming ratio than the conventional polyamide foams while still exhibiting excellent mechanical properties. Often, an addition of higher amount of isocyanate compound to polyamide matrix can result in a higher foaming ratio in the polyamide foam, yet such use of higher amount of isocyanate compound may degrade the mechanical properties of the polyamide foam, such as flexural strength, flexural modulus and impact strength, which are necessarily required in certain applications.
Therefore, the foamable polyamide composition which can attain a high degree of foaming with a less addition of isocyanate compound is required in this technology field.